Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A yeast strain Kluyveromyces with high inulinase yield was screened. The highest inulinase activity of 288.78 u/mL was reached when a high cell density cultivation method was developed for inulinase production. It was 6.8 times higher than the highest level reported in the same species. The activity ratio of its inulinase to invertase was 1/24.72, the Km values were 13.3 mmol/L and 62.6 mmol/L when inulin and sucrose were used as substrate, respectively; The optimum pH value was 4.4, this enzyme also showed a good pH adaptability and stability, i.e. more 90% of the highest level was maintained between pH 3.8 and 5.6; The optimum reaction temperature was 55 degrees C, higher activity was maintained between 50-57.5 degrees C, its half life period was 16 hours at 55 degrees C; It was found for the first time that addition of magnesium ion into the reaction system increased the enzyme activity by 11%.
 ...
PMID:[A study on screening and high density cell cultivation of a yeast strain Kluyveromyces with high inulinase yielding and its enzymology properties]. 1088 78

The main component of inulinase was purified from fermentation broth of Aspergillus niger 319 to homogeneity by using ammonium sulfate fraction, ion-exchange chromatography on DEAE-cellulose column and Sephadex G-100 gel filtration. The specific activity was as 67 folds at the fermentation broth, and the yield was 25.5%. The inulinase, containing 13.92% of carbohydrate, was a monomer protein with a molecular weight of 28,000 Dalton; and its isoelectric point was pH 5.4. The optimal pH and temperature of the inulinase was pH 5.0 and 60 degrees C, respectively. The enzyme was strongly inhibited by heavy metal ions of Hg2+, Pb2+ and Cu2+. The optimal substrate for the enzyme was inulin and the product was only fructose, but it also had invertase activity with the I/S of 0.348. The Km and Vm of the inulinase was 6.25 mmol/L and 67.11 mumol.mg-1.min-1, respectively.
 ...
PMID:[Purification and properties of inulinase from Aspergillus niger]. 1118 61

Inulinase and Invertase Activities, Thermophilic Bacilli, Enzyme Thermostability Enzyme production of newly isolated thermophilic inulin-degrading Bacillus sp. 11 strain was studied by batch cultivation in a fermentor. The achieved inulinase and invertase activities after a short growth time (4.25 h) were similar or higher compared to those reported for other mesophilic aerobic or anaerobic thermophilic bacterial producers and yeasts. The investigated enzyme belonged to the exo-type inulinases and splitted-off inulin, sucrose and raffinose. It could be used at temperatures above 65 degrees C and pH range 5.5-7.5. The obtained crude enzyme preparation possessed high thermostability. The residual inulinase and invertase activities were 92-98% after pretreatment at 65 degrees C for 60 min in the presence of substrate inulin.
 ...
PMID:Production and properties of a bacterial thermostable exo-inulinase. 1183 54

The gene encoding a 2,6-beta-D-fructan 6-levanbiohydrolase (LF2ase) (EC 3.2.1.64) that converts levan into levanbiose was cloned from the genomic DNA of Streptomyces exfoliatus F3-2. The gene encoded a signal peptide of 37 amino acids and a mature protein of 482 amino acids with a total length of 1560 bp and was successfully expressed in Escherichia coli. The similarities of primary structure were observed with levanases from Clostridium acetobutylicum, Bacillus subtilis, B. stearothermophilus (51.0-54.3%) and with LF2ase from Microbacterium levaniformans (53.9%). The enzyme from S. exfoliatus F3-2 shared the conserved six domains and the completely conserved five amino acid residues with family 32 glycosyl hydrolases, which include levanase, inulinase, and invertase. These observations led to the conclusion that the enzyme belongs to family 32 glycosyl hydrolases.
 ...
PMID:Molecular cloning of the gene for 2,6-beta-D-fructan 6-levanbiohydrolase from Streptomyces exfoliatus F3-2. 1258 2

Exo-inulinases hydrolyze terminal, non-reducing 2,1-linked and 2,6-linked beta-d-fructofuranose residues in inulin, levan and sucrose releasing beta-d-fructose. We present the X-ray structure at 1.55A resolution of exo-inulinase from Aspergillus awamori, a member of glycoside hydrolase family 32, solved by single isomorphous replacement with the anomalous scattering method using the heavy-atom sites derived from a quick cryo-soaking technique. The tertiary structure of this enzyme folds into two domains: the N-terminal catalytic domain of an unusual five-bladed beta-propeller fold and the C-terminal domain folded into a beta-sandwich-like structure. Its structural architecture is very similar to that of another member of glycoside hydrolase family 32, invertase (beta-fructosidase) from Thermotoga maritima, determined recently by X-ray crystallography The exo-inulinase is a glycoprotein containing five N-linked oligosaccharides. Two crystal forms obtained under similar crystallization conditions differ by the degree of protein glycosylation. The X-ray structure of the enzyme:fructose complex, at a resolution of 1.87A, reveals two catalytically important residues: Asp41 and Glu241, a nucleophile and a catalytic acid/base, respectively. The distance between the side-chains of these residues is consistent with a double displacement mechanism of reaction. Asp189, which is part of the Arg-Asp-Pro motif, provides hydrogen bonds important for substrate recognition.
 ...
PMID:Crystal structure of exo-inulinase from Aspergillus awamori: the enzyme fold and structural determinants of substrate recognition. 1552 99

Fructo-oligosaccharide represent one of the major classes of bifidogenic oligosaccharides in term of their production volume, because of their favorable functional properties. These include: a/ improving the intestinal microflora; b/ relieving the constipation; c/ decreasing the total cholesterol and lipid in serum; d/ the promotion of animal growth and e/ as low calorie non-cariogenic sweeteners (Chen and Liu, 1996). FOS are manufactured by two differing processes which result in slightly different end products--using either microbial fructosyl transferase (EC 2.4.1.9) or beta-fructofuranosidase (EC 3.2.1.26) with high transfructosylation activity. The present study reports on the biosynthesis of an extracellular inulinase by yeasts from genus Kluyveromyces. The strains were isolated from different dairy products. Some of the studied strains produced large amounts of extracellular inulinase activity when grown on inulin ar sucrose as carbon source. In addition, the effect of C/N ratio on the production of extracellular inulinase was studied. Thin layer chromatography showed that inulinase from K. species 19 was capable of hydrolyzing inulin, releasing monosaccharides and oligosaccharides.
 ...
PMID:A study of extracellular inulinase activity in strains of genus Kluyveromyces. 1595 93

Like barley and other cereals, wheat (Triticum aestivum L.) accumulates branched graminan-type fructans containing both beta-(2,1) and beta-(2,6) fructosyl linkages, mainly with a quite low degree of polymerization (DP). 1&6-kestotetraose (bifurcose) is the major fructan oligosaccharide accumulating in crown tissues and leaves of cereals exposed to chilling. The fructan exohydrolase (FEH) cDNAs 1-FEH w1 and w2 were previously cloned from wheat crowns sampled in mid-November. Here, we report the cloning and functional analysis of another FEH cDNA from a mid-November wheat crown cDNA library. The cDNA encodes a long open reading frame (ORF) of 595 amino acids. Like other FEHs, it has a low iso-electric point (5.2) and it groups together with cell-wall type invertases and not with vacuolar invertases. The deduced amino acid sequence shows 67% identity to wheat 1-FEH w1 and w2. Functional characterization of the recombinant proteins in Pichia pastoris demonstrated that the recombinant enzyme had FEH activity towards the pure compounds 1-kestose, 6-kestose, 1,1-nystose and 1,1,1-kestopentaose. However, when incubated with its putative natural substrates (a mixture of low DP graminans from wheat crowns), it was shown that 1&6-kestotetraose (bifurcose) was preferentially removed from the graminan mixture. High DP wheat graminan and bacterial levan were only poor substrates. No hydrolase activities could be detected towards sucrose and high DP inulin, convincingly demonstrating that the enzyme is not a classic invertase or 1-FEH. The enzyme was termed 6&1-FEH w1. Northern blot analyses showed that 6&1-FEH w1 was expressed in crown tissue from autumn through winter under snow, while the expression levels in leaves were minimal or not detectable. The results strongly suggest that this unique FEH might play an important role in the degradation of branched, low DP wheat graminan (like bifurcose) in wheat crowns in the high fructan content season.
 ...
PMID:Molecular cloning and functional analysis of a novel 6&1-FEH from wheat (Triticum aestivum L.) preferentially degrading small graminans like bifurcose. 1605 49

An endoinulinase produced by Chaetomium sp. C34 was purified to electrophoretic homogeneity, with recovery of 7.7% activity and purification factor of 30.8 fold by five steps including ammonium sulfate precipitation, DEAE-cellulose, Q-sepharose Fast Flow, Sephacryl S-200 and Pre-Packed Hydrophobic Column. Its subunit molecular weight was estimated to be about 66kD by SDS-PAGE. The optimum temperature and pH of the enzyme activity were 50 approximately 55 degrees C and 6.0 respectively. The K(m) and V(max) values for inulin were 0.199 mmol/L and 115 micromol/(mg x min) respectively. Cu2+ completely inhibited inulinase activity. An appreciable loss of activity was observed in presence of NBS, Mn2+, Zn2+, Fe2+ and EDTA. A ratio of inulinase activity to invertase activity (I/S) of 20 was found in purified inulinase. The endoinulinase hydrolyzed inulin and liberated inulooligosaccharides. But it lacked activity toward melezitose or raffinose.
 ...
PMID:[Purification and properties of endoinulinase from Chaetomium sp]. 1611 Sep 61

The enzymological studies on the sediment of the accumulation lake that has the main purpose of supplying drinking water to the city of Cluj-Napoca and the nearby villages, were aimed at the comprehensive understanding of the complex processes that happen in these habitats of special significance. In the sediment samples the following enzymatic activities have been quantitatively determined: phosphatase, actual and potential dehydrogenase, catalase, urease and protease. Non-enzymatic catalytic activity was also measured. Based on the relative values for the enzymatic activities, the enzymatic indicator of the sediment quality (EISQ) was calculated (ranging from 0.1 to 0.7). The enzymatic activities have been qualitatively determined for maltase, saccharase, lactase, cellobiase, amylase, dextranase, levanase, cellulase and inulinase. The correlation between the enzymatic and bacteriologic potential was statistically calculated.
 ...
PMID:The enzymatic activity from the sediment of the Gilau dam reservoir - Cluj county. 1662 16

As a soil fungus, Aspergillus niger can metabolize a wide variety of carbon sources, employing sets of enzymes able to degrade plant-derived polysaccharides. In this study the genome sequence of A. niger strain CBS 513.88 was surveyed, to analyse the gene/enzyme network involved in utilization of the plant storage polymer inulin, and of sucrose, the substrate for inulin synthesis in plants. In addition to three known activities, encoded by the genes suc1 (invertase activity; designated sucA), inuE (exo-inulinase activity) and inuA/inuB (endo-inulinase activity), two new putative invertase-like proteins were identified. These two putative proteins lack N-terminal signal sequences and therefore are expected to be intracellular enzymes. One of these two genes, designated sucB, is expressed at a low level, and its expression is up-regulated when A. niger is grown on sucrose- or inulin-containing media. Transcriptional analysis of the genes encoding the sucrose- (sucA) and inulin-hydrolysing enzymes (inuA and inuE) indicated that they are similarly regulated and all strongly induced on sucrose and inulin. Analysis of a DeltacreA mutant strain of A. niger revealed that expression of the extracellular inulinolytic enzymes is under control of the catabolite repressor CreA. Expression of the inulinolytic enzymes was not induced by fructose, not even in the DeltacreA background, indicating that fructose did not act as an inducer. Evidence is provided that sucrose, or a sucrose-derived intermediate, but not fructose, acts as an inducer for the expression of inulinolytic genes in A. niger.
 ...
PMID:Database mining and transcriptional analysis of genes encoding inulin-modifying enzymes of Aspergillus niger. 1700 86


<< Previous 1 2 3 4 5 6 Next >>